Expt. 7 Velocity of Sound
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Transcript of Expt. 7 Velocity of Sound
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Experiment 7
Speed of Sound
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The Nature of Sound Waves
1. A wave is a traveling disturbance.
2. A wave carries energy from place to place.
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The Nature of Sound Waves
Transverse Wave
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The Nature of Sound Waves
Longitudinal Wave
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Periodic Waves
Periodic waves consist of cycles or patterns that are produced over and
over again by the source.
In the figures, every segment of the slinky vibrates in simple harmonic
motion, provided the end of the slinky is moved in simple harmonic
motion.
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In the drawing, one cycle is shaded in color.
The amplitude A is the maximum excursion of a particle of the medium from
the particles undisturbed position.
The wavelength is the horizontal length of one cycle of the wave.
The period is the time required for one complete cycle.
The frequency is related to the period and has units of Hz, or s-1.
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Periodic Waves
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The Nature of Sound Waves
LONGITUDINAL SOUND WAVES
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The Nature of Sound Waves
The distance between adjacent condensations is equal to the
wavelength of the sound wave.
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The Nature of Sound Waves
Individual air molecules are not carried along with the wave.
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The Nature of Sound Waves
THE FREQUENCY OF A SOUND WAVE
The frequency is the number of cycles
per second.
A sound with a single frequency is called
a pure tone.
The brain interprets the frequency in terms
of the subjective quality called pitch.
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The Nature of Sound Waves
THE PRESSURE AMPLITUDE OF A SOUND WAVE
Loudness is an attribute of
a sound that depends primarily
on the pressure amplitude
of the wave.
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The Speed of Sound
Sound travels through gases,
liquids, and solids at considerably
different speeds.
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The Speed of Sound
Conceptual Example Lightning and Thunder
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The Speed of Sound
SOLID BARS
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Applications of Sound in Medicine
By scanning ultrasonic waves across the body and detecting the echoes
from various locations, it is possible to obtain an image.
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Applications of Sound in Medicine
Ultrasonic sound waves cause
the tip of the probe to vibrate at
23 kHz and shatter sections of
the tumor that it touches.
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Applications of Sound in Medicine
When the sound is reflected
from the red blood cells, its
frequency is changed in a
kind of Doppler effect because
the cells are moving.
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Activity 1: Velocity of Sound in Air
Temperature of air = Diameter of Resonance Tube =
Tuning Fork Wavelength (m) Average
Wavelength
Experimenta
l speed
Theoretical
speed
% error
Trial 1 Trial 2 Trial 3
DL 3.04
Tube open at one end
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Activity 1: Velocity of Sound in Air
DL 3.04
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Activity 2: Speed of Sound (Expt. 24 of Physics with Computers)
Trial Total Travel Time
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2
3
Average
Experimental speed
Theoretical speed
%error
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Activity 2: Speed of Sound (Expt. 24 of Physics with Computers)
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Activity 3: Velocity of Sound in Solid
Average of distances between node to node
Wavelength of sound in air
Frequency of sound in air
Frequency of sound
Length of rod
Wavelength of sound in air
Experimental speed of sound in the rod
Theoretical speed of sound in the rod
% error
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Activity 3: Velocity of Sound in Solid
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